1. Field of the Invention
This invention relates generally to supporting rollers and more particularly to a novel adjustably supporting roller device for sliding patio doors and other uses.
2. Discussion of the Prior Art
Generally speaking, the invention provides an adjustable supporting roller unit whose supporting roller is adjustable to a retracted position to shield the unit against damage during storage and handling of the object to be supported and to an extended position for use. While capable of a variety of uses, the roller unit is intended primarily for use as a supporting roller for a sliding door, such as a sliding patio door, and will be described in this context.
A conventional sliding patio door installation has a door frame with a track along the lower side of the door frame opening and at least one fixed door panel and one sliding door panel in the frame opening. The sliding panel is moveable edgewise between open and closed positions. To this end, the lower edge of the sliding door panel mounts supporting rollers which ride in the lower door frame track and the upper door edge is guided in the upper side of the frame, as by sliding engagement within a channel along the upper side.
A vast assortment of supporting roller devices have been devised for such sliding doors. Examples of such roller devices are described in my prior U.S. Pat. Nos. 3,443,340; 3,613,313; 3,879,893; 4,064,593.
The present invention is concerned with one problem which is commonly encountered in connection with such doors. The problems referred to stems from the fact that the supporting rollers along the lower door edge are commonly biassed by springs to extended positions wherein the rollers project beyond the edge. In addition, during storage, such doors are often stood upright to rest on their lower edges and during handling and shipment, the doors are often slid on their lower edges across the floors. As a consequence, the spring extended door rollers are frequently damaged during storage and handling.